U.S. patent number 5,135,528 [Application Number 07/710,326] was granted by the patent office on 1992-08-04 for hockey stick chisel.
Invention is credited to Frederick Winston.
United States Patent |
5,135,528 |
Winston |
August 4, 1992 |
Hockey stick chisel
Abstract
A medical instrument for performing a vertebral osteotomy
comprising an elongated handle member having first and second ends
and a curved blade member extending from the second end of the
handle, which curved blade member terminates in a chisel at a
forward edge. The forward tip of the chisel is chamfered so as to
safeguard against contacting the spinal cord during the vertebral
osteotomy.
Inventors: |
Winston; Frederick (Cincinnati,
OH) |
Family
ID: |
24853565 |
Appl.
No.: |
07/710,326 |
Filed: |
June 4, 1991 |
Current U.S.
Class: |
606/79;
606/81 |
Current CPC
Class: |
A61B
17/1604 (20130101); A61B 17/1671 (20130101) |
Current International
Class: |
A61B
17/16 (20060101); A61B 017/00 () |
Field of
Search: |
;606/79,84,85,184,185,186 ;30/314,167,167.1,DIG.8 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
1082411 |
|
Mar 1984 |
|
SU |
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1162415 |
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Jun 1985 |
|
SU |
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Primary Examiner: Brown; Michael A.
Attorney, Agent or Firm: Wood, Herron & Evans
Claims
What is claimed is:
1. A medical instrument for performing a vertebral osteotomy
comprising:
an elongated handle member having first and second ends, and
a planar curved blade member extending from said second end of said
handle and adapted to be inserted between adjacent vertebrae, said
curved blade member terminating in a chisel at a forward edge
thereof, said chisel having a chamfered non-cutting edge extending
generally from said forward edge to an inner side of said
chisel.
2. The medical instrument of claim 1 wherein said curved blade
member tapers gradually to said chisel.
3. The medical instrument of claim 2 wherein said curved blade
member has a radius of curvature of about 0.31 inches.
4. The medical instrument of claim 2 wherein said curved blade
member has a radius of curvature ranging from about 0.2 inches to
about 0.5 inches.
5. The medical instrument of claim 4 wherein said curved blade
member has a width dimension ranging from about 0.2 inches to about
0.5 inches.
6. The medical instrument of claim 5 wherein said curved blade
member is oriented with respect to said handle member at an angle
ranging between about 30.degree. and about 70.degree..
7. The medical instrument of claim 6 wherein a forward tip of said
chisel extends from said blade member in an amount ranging from
about 0.2 inches to about 0.4 inches.
8. The medical instrument of claim 5 wherein said curved blade
member is oriented with respect to said handle member at an angle
of about 45.degree..
9. The medical instrument of claim 6 wherein a forward tip of said
chisel extends from said blade member by about 0.31 inches.
10. The medical instrument of claim 4 wherein said curved blade
member has a width dimension of about 0.31 inches.
Description
FIELD OF THE INVENTION
This invention relates to medical instruments, and more
particularly to a medical instrument for use during a vertebral
osteotomy.
BACKGROUND OF THE INVENTION
Back surgery, and particularly the vertebral osteotomy procedure,
has heretofore been difficult and cumbersome to perform due to the
geometry of the operative site. Specifically, the operative site
comprises a spinal cord and a plurality of vertebrae surrounding
the spinal cord along its length. In a vertebral osteotomy, facing
sides of the bodies of two adjacent vertebrae are trimmed or
otherwise cut away. Difficulties are encountered, however, as the
bone which is cut away from the vertebral body is located anterior
of the spinal cord. It will be appreciated that a surgeon's vision
or line of sight is impaired in this type of procedure, since in a
vertebral osteotomy the patient lies prone, and this causes the
spinal cord to block the view of that portion of the vertebral body
which is sought to be cut or trimmed away.
Further complicating the vertebral osteotomy is the fact that a
sharpened cutting instrument or chisel, known as an osteotome, must
be utilized to cut or otherwise trim away portions of the bony
vertebral body. However, such trimming and cutting takes place in
the vicinity of the delicate spinal cord, which lies in a canal
formed by the vertebral bodies, pedicles, and laminae.
SUMMARY OF THE INVENTION
It has therefore been one objective of the present invention to
provide a medical instrument wherein a vertebral osteotomy is
facilitated when the vertebral bone which is sought to be cut away
is located anterior of a patient's spinal cord.
It has been another objective of the present invention to provide a
medical instrument wherein the vertebral bone is sought to be cut
away is located anterior of a patient's spinal cord and which
safeguards against coming in contact with the spinal cord.
The present invention is a medical instrument for performing a
vertebral osteotomy comprising an elongated handle member having
first and second ends and a curved blade member extending from the
second end of the handle, which curved blade member terminates in a
chisel at a forward edge thereof. The forward tip of the chisel is
chamfered so as to safeguard against contacting the spinal
cord.
One advantage of the present invention is that a vertebral
osteotomy is facilitated wherein the bony portion of the vertebral
body which is sought to be removed is located anterior of the
spinal cord.
Another advantage of the present invention is that a medical
instrument has been provided which during a vertebral osteotomy
safeguards against contacting the spinal cord.
These and other objects and advantages of the present invention
will become more readily apparent during the following detailed
description taken in conjunction with the drawings herein, in
which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the medical instrument of the
present invention;
FIG. 2 is an enlarged view of the chisel of the medical instrument
of the present invention; and
FIG. 3 is an illustration of the use of the medical instrument of
the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIG. 1, there is illustrated the medical
instrument of the present invention, or so-called hockey stick
chisel 1. The hockey stick chisel 1 is preferably fabricated of
high grade stainless steel and comprises, generally, an elongated
handle member 5, a planar curved blade member 6 extending from the
lower end of the handle 5, and a sharpened tip or chisel 7.
The handle 5 includes an upper cylindrical grasping portion 15 and
a lower necked-down portion 16 which connects the grasping portion
15 with the curved blade member 6.
As shown in FIG. 1, curved blade member 6 has a radius of curvature
10 which ranges between about 0.2 inches and about 0.5 inches, and
which, preferably, is about 0.31 inches. The curved blade member 6
has a width 11 which ranges between about 0.2 inches and about 0.5
inches, and which ideally is equal to about 0.31 inches. The curved
blade member 6 is oriented with respect to the handle member 5 at
an angle 12 which ranges between about 30.degree. and 70.degree.,
and which preferably is about 45.degree..
Chisel 7 has a bone cutting edge 20 formed by beveling both sides
of thee curved blade member 6. This chisel 7 extends about 0.2
inches to 0.4 inches, and preferably about 0.31 inches, from the
forward edge 6a of the blade member 6 as illustrated at 21. The
chisel 7 has a chamfered non-cutting edge 22 (FIG. 2), thereby
eliminating what would be the forward tip of the chisel 7.
With reference to FIG. 3, there will be seen the hockey stick
chisel 1 of the present invention as utilized during a vertebral
osteotomy. For this procedure, the operative sight 30 includes
adjacent vertebrae 31 and 32 which comprise, respectively, body
31a, pedicle 31b and lamina 31c, and body 32a, pedicle 32b and
lamina 32c. Spinal cord 33 lies in the canal formed by the
vertebral bodies 31a and 32a, pedicles 31b and 32b, and laminae 31c
and 32c. Vertebral rims 31d and 32d, which are sought to be removed
during a vertebral osteotomy, appear on facing sides 31e and 32e of
the adjacent vertebral bodies 31a and 32a.
To perform the vertebral osteotomy, the operative sight 30 is first
exposed. Then the curved blade member 6 is inserted between bodies
31a and 32a of vertebrae 31 and 32. The chisel 7 is then worked
into the gap between facing sides 31e and 32e of vertebrae 31 and
32. The chisel edge 20 of the chisel 7 is then employed to slice or
cut away the vertebral rims 31d and 32d on the facing sides 31e and
32e of the adjacent vertebral bodies 31a and 32a.
The instrument 1 is advantageously designed to facilitate the
vertebral osteotomy. The width 11 of the curved blade member 6 in
conjunction with the angle 12 which this curved blade member 6 is
oriented with respect to the handle 5 allows for the trimming away
of vertebral rims 31d and 32d. The dimension 21 by which the chisel
edge 20 extends from the forward edge 6a of the curved blade member
6 additionally facilitates the trimming and cutting away of the
vertebral rims 31d and 32d. And, the bevel 22 on the chisel 7
safeguards against the instrument 1 contacting the spinal cord
33.
Those skilled in the art will readily recognize adaptations and
modifications which can be made to the medical instrument of the
present invention which result in an improved medical instrument
yet without departing from the spirit or scope of the present
invention. Accordingly, I intend to be limited only by the broad
scope of the appended claims.
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